What are the Work Classifications of Low Nitrogen Burners?
What are the Work Classifications of Low Nitrogen Burners?
Low nitrogen burners are burners that emit low nitrogen oxides during fuel combustion. Traditional natural gas boiler burners typically emit around 120-150mg/m3 of NOx. Low nitrogen burners typically emit around 30-80mg/m3 of NOx. Burners that emit less than 30mg/m3 of NOx are typically referred to as low nitrogen burners. Currently, low nitrogen burners are mainly divided into the following categories based on their principles: Staged combustion burners designed according to staged combustion principles mix the fuel and air in stages, and due to the combustion deviation from the theoretical equivalence ratio, it can reduce the generation of nitrogen.
Low nitrogen burners are a type of burner that uses the head pressure of the combustion air to draw back part of the combustion smoke and mix it with the air in the burner for combustion. Due to the re-circulation of smoke, the heat capacity of the combustion smoke is large, the temperature of the combustion flame decreases, and NOx production is reduced. Another type of self-circulating burner is one that re-circulates a portion of the smoke directly in the burner and adds it to the combustion process. Low nitrogen burners have a dual function of inhibiting nitrogen oxides and saving energy. The principle is to make some of the fuel burn too rich and some of the fuel burn too lean, but to maintain the same overall airflow. Due to these two parts burning off-chemistry, the NOx is very low. This type of combustion is also referred to as biased combustion or non-stoichiometric combustion.
The principle of low-nitrogen burners is to divide one flame into several small flames. Due to the large heat dissipation area of the small flames and the low flame temperature, the “heat reaction NO” is reduced. In addition, the small flames shorten the residence time of gases such as oxygen and nitrogen in the flame, which has a significant inhibitory effect on “heat reaction NO” and “fuel NO”. The residence time of smoke in the high-temperature area is one of the main factors affecting NOx generation. Improving the mixing of the combustion and air can reduce the thickness of the flame surface. For continuous reliable low nitrogen combustion in industrial boilers, it is not enough to only replace or modify the burner. It is also necessary to upgrade the combustion control device, such as adding “real-time control”, “burner control devices”, etc.